Adaptive Subcarrier Allocation Algorithm for Multi-User Systems Under Beam Split Scenario in THz Band

Terahertz (THz) communication is regarded as one of the key technologies for future 6G wireless communication. To mitigate the severe path loss associated with high-frequency signals, hybrid precoding architectures are typically employed to provide high-gain beams. However, in MIMO systems based on hybrid precoding structures, the beam split effect caused by frequency-independent phase shifters becomes a critical challenge, particularly in the THz frequency band. Specifically, the beams at the edge subcarriers deviate from those designed for the center subcarrier, leading to significant performance degradation. Unlike existing schemes that introduce delay adjustment modules, this paper proposes a novel approach that leverages beam split to design a multi-user subcarrier allocation algorithm according to the different beam directions, thereby achieving higher communication performance across the entire bandwidth. Simulation results demonstrate that the proposed method significantly enhances the average spectral efficiency within the beam split range, and the performance improvement becomes more pronounced as the number of users increases.